The noun 杀手 (shāshǒu) means "killer" or "assassin," referring to someone or something that causes death or destruction. It can be used literally for a person who kills, or figuratively to describe something devastating, such as a "killer" disease or competitive threat. It often appears in dramatic or journalistic contexts.
这种病毒是老年人的隐形杀手。
Zhè zhǒng bìngdú shì lǎoniánrén de yǐnxíng shāshǒu.
This virus is a silent killer of the elderly.
电影里的杀手看起来很冷酷。
Diànyǐng lǐ de shāshǒu kàn qǐlái hěn lěngkù.
The killer in the movie looks very cold-blooded.
高血压被称为健康的头号杀手。
Gāo xuèyā bèi chēng wéi jiànkāng de tóuhào shāshǒu.
High blood pressure is known as the number one killer of health.